CsvParser.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Containers/Array.h"
#include "Containers/UnrealString.h"
 
/** A simple, efficient csv parser */
struct FCsvParser
{
    typedef TArray<TArray<const TCHAR*>> FRows;
 
    /**
     *  Construct with a string.
     *  Takes a copy because the parser tramples over the file to create null-terminated cell strings
     *  Avoid a copy by passing overship of the source string with MoveTemp()
     */
    FCsvParser(FString InSourceString);
 
    /**
     *  Const access to the parsed rows
     *  Rows are stored as arrays of parsed, null-terminated cell-strings.
     *  Object (and contained strings) is valid for the lifetime of the parser.
     */
    const FRows& GetRows() const
    {
        return Rows;
    }
 
private:
    /** Non copyable - has pointers to itself */
    FCsvParser(const FCsvParser&);
    FCsvParser& operator=(const FCsvParser&);
 
    /** Internal enum to control parsing progress */
    enum struct EParseResult { EndOfCell, EndOfRow, EndOfString };
 
    /** Parse all the rows in the source data */
    void ParseRows();
 
    /** Parse a single row at the current read position */
    EParseResult ParseRow();
 
    /** Parse a cell at the current read position */
    EParseResult ParseCell();
 
private:
 
    /** Raw csv buffer, sliced and diced by the parser */
    FString SourceString;
 
    /** Fixed pointer to the start of the buffer */
    TCHAR* BufferStart;
 
    /** Current parser read position */
    const TCHAR* ReadAt;
 
    /** Array of cell string arrays */
    FRows Rows;
 
private:
 
    /** Helper to measure the size of a new line at the current read position */
    int8 MeasureNewLine(const TCHAR* At);
};